Lavatory service shut off valve

ABSTRACT

A shut off valve is provided for use in an aircraft lavatory system during maintenance sanitizing operations. The shut off valve includes an inlet passage in intermittent fluid communication with an outlet passage and a magnetic flapper body movable between a rest position and a seal position between said inlet passage and said outlet passage. The flapper body is moved by a magnetic actuator whereby upon placing said magnetic actuator within the proximity of the flapper body, the flapper body is moved from the rest position and, with the assistance of fluid flow within the valve, into the seal position, thus, preventing fluid communication between the inlet passage and the outlet passage.

FIELD OF THE INVENTION

[0001] This invention relates generally to fluid shut off valves andmore specifically to an automatic shut off valve using magneticactuation.

BACKGROUND OF THE INVENTION

[0002] The modern aircraft lavatory uses the flow of disinfectant fluidor a powerful pump to remove waste from a toilet into a waste holdingtank. During ground maintenance the waste tank is emptied and sanitized.Sanitation is especially important to kill any infectious disease agentspotentially carried in human waste. The emptying and sanitizingprocesses are typically performed by airport ground crews using alavatory cart. The cart includes a supply of disinfectant fluid as wellas a disposal tank. Disinfectant fluid is pumped into the aircraft wasteholding tank after waste from the flight is drained.

[0003] In order to do an effective job of sanitizing the aircraft wastestorage tank, it is desirable to fill the waste storage tank up to aspecific level. Filling to a high level has many potential drawbacks ifoverfilling occurs. Overfilling can create spillage of disinfectantfluid, potentially contaminated with human waste. Spilled disinfectantfluid can freeze at high altitudes, creating solid projectiles,sometimes referred to as blue ice, which are potentially dangerous tothe aircraft, especially its engines. Disinfectant fluid is harmful tothe aircraft structure and electronics. Disinfectant fluid also includesa strong smelling detergent which when spilled on the interior of theaircraft via overfilling the toilet is objectionable, thus, it isdesirable to minimize spills.

[0004] A valve which can automatically prevent overfilling of the wasteholding tank is desired. An additional desire is to provide a valve withautomatic shut off for use during the filling operation in combinationwith a backflow prevention device for use during normal operations.

SUMMARY OF THE INVENTION

[0005] The present invention is directed to an automatic shut off valveand to an aircraft lavatory system which may be sanitized while avoidingany overfilling of the sanitary waste holding tank.

[0006] In one embodiment the invention provides a shut off valve forregulating fluid flow which includes an inlet passage in intermittentfluid communication with an outlet passage, a magnetic flapper bodymovable between a rest position and a seal position between the inletpassage and the outlet passage and a magnetic actuator that moves theflapper body toward a seal position, thus, preventing fluidcommunication between the inlet passage and the outlet passage.

[0007] In another embodiment the invention provides a lavatory systemfor use on an airplane which includes one or more toilets, each toiletincluding a drain passage for disposal of sanitary wastes. The systemalso includes a waste tank attached to the drain passages from saidtoilets, a shut off valve for regulating flow of disinfectant fluid usedto rinse the waste tank, a vertically canted tube in fluid communicationwith the waste tank, and a magnetic float within the tube whereby thefloat rises and falls in response to level changes within the wastetank. The shut off valve includes an inlet passage in intermittent fluidcommunication with an outlet passage, which directs fluid to the wastetank. The valve also includes a magnetic flapper body movable between arest position and a seal position between the inlet passage and theoutlet passage. When a predetermined level is reached in the waste tank,the magnetic float comes within the proximity of the magnetic flapperbody, and the flapper body is moved from a rest position and, with theassistance of fluid flow pressure into a seal position.

[0008] The present invention provides numerous advantages not realizedin the prior art. First, the invention provides a no-spill fillingsystem, thus, avoiding potential freezing of spilled fluid and avoidingthe problems associated with a spilled, highly aromatic and corrosivefluid. The invention also provides a shut off valve which may beactuated magnetically, avoiding the need for a mechanical actuator. As aresult, the valve may be constructed with fewer parts and seals whichminimizes potential failures. Additionally, the shut off valve withinthe system functions automatically thereby eliminating the need forairline ground crews to consistently check the level of disinfectantfluid being fed into the waste tank during sanitizing operations. Thus,the valve serves as a backup if the ground crew forgets to shut off theinlet supply at the appropriate level from the truck.

[0009] These and other features, aspects and advantages of the presentinvention will be fully described by the following description, appendedclaims, and accompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES

[0010]FIG. 1 is a cutaway view of the shut off valve;

[0011]FIG. 2 is a schematic of the layout of an aircraft lavatory;

[0012]FIG. 3 is a perspective view of an aircraft and lavatory cart; and

[0013]FIG. 4 is a perspective view of a waste tank.

DETAILED DESCRIPTION OF THE INVENTION

[0014] Referring to FIG. 1 a shut off valve 10 is shown for use in anaircraft lavatory system. The shut off valve 10, as described in moredetail below, functions to prevent overfilling of a waste tank withdisinfectant fluid.

[0015] The shut off valve 10 includes a valve body 12. The valve body 12may be made from non-magnetic, non-corrosive materials havingcharacteristics of high strength. The shut off valve 10 includes aninlet passage 20 through which disinfectant fluid enters the shut offvalve 10 and an outlet passage 30 through which disinfectant fluid exitsthe shut off valve 10. The shut off valve includes a flapper body 40situated within the inlet passage 20 which regulates the intermittentfluid communication between the inlet passage 20 and the outlet passage30. When the flapper body 40 is in a rest position, fluid may pass fromthe inlet passage 20 into the outlet passage 30. When the flapper body40 is in a seal position, fluid is prevented from passing from the inletpassage 20 into the outlet passage 30.

[0016] The flapper body 40 is a magnetic piece which has the ability toblock the outlet passage 30. The flapper body 40 may be manufacturedfrom a magnetic material or may be manufactured from a non-magneticmaterial and have one or more magnets 42 attached to its surface. Theflapper body is hinged at one end to the shut off valve body 12 allowingthe flapper body 40 to rotate from a rest position to a seal position.The seal position has the flapper body 40 covering the outlet passage30. The rest position has the flapper body 40 resting upon the valvebody 12. The valve body 12 may be manufactured with a cavity 14 whichprovides a place for the flapper body 40 to rest. The size and shape ofthe cavity are designed based on numerous factors including the flowrateof fluid through the valve 10, the density of the fluid, the flapperbody 40 shape, the weight of the flapper body 40, and length andorientation of the inlet passage 20. When the flapper body 40 is withinthe cavity 14 the flow of fluid in the inlet passage 20 is notdisturbed.

[0017] The shut off valve 10 may also include a check valve 50. Thecheck valve 50 functions to prevent back flow of any fluid, namely humanwaste within the waste tank during normal, non-sanitizing operations.These materials can hinder the function of the flapper body 40. Thecheck valve 50 may be situated within or adjacent to either the inletpassage 20 or the outlet passage 30. The check valve 50 may be any typeknown in the art including ball check and flapper check types. The checkvalve 50 may be manufactured as part of the valve body 12 oralternatively may be a fitting which is able to attach to the valve body12.

[0018] The shut off valve 10 includes a magnetic actuator 60. Themagnetic actuator 60 functions to move the flapper body 40 from its restposition. Movement occurs when the magnetic actuator 60 is brought intoclose proximity to the flapper body 40. Magnetic forces between themagnetic actuator 60 and the flapper body 40 cause movement of theflapper body 40. In one embodiment of the invention repelling magneticforces are used. In another embodiment (not illustrated) the flapperbody 40 is situated on a fulcrum and attractive magnetic forces are usedto move one end of the flapper body towards the magnetic actuator 60while the other end rotates to seal the outlet passage 30. In oneembodiment of the invention, the magnetic actuator 60 is a float. Risingand falling fluid levels move the magnetic actuator 60 into and out ofproximity of the flapper body 40. In another embodiment of the inventionthe actuator 60 is not magnetic, but is a float which triggers astationary electromagnet at a set level. The electromagnet then actuatesthe flapper body 40. There is no requirement for the magnetic actuator60 to ever be in contact with the flapper body 40. Thus, the valve body12 may be a sealed unit and as the magnetic actuator 60 approaches theoutside of the valve body 12, the flapper body 40 is moved.

[0019] The valve body 12 may also include a reset magnet 44. The resetmagnet 44 helps move or keep the flapper body 40 in a rest position whensealing of the outlet passage 30 is not desired. The reset magnet 44generates a magnetic force which repels the flapper body 40 or magnets42 thereupon. The reset magnet 44, due to its position or inherentmagnetic force does not create a force which exceeds the force generatedby a magnetic actuator 60 and the pressure of flow through the inletpassage 20. Thus, when the magnetic actuator 60 is in a proximalposition, the force it generates can overcome the force generated by thereset magnet 44 and the flapper body 40 may be moved towards a sealposition with the aid of the pressure of flow through the inlet passage20. The valve body 12 may also be manufactured with a bypass passage 16.The bypass passage 16 directs a small amount of fluid through adifferent portion of the valve body 12 to provide rinsing of the float60. The bypass passage flow rate depends on the backpressure created inthe system when disinfectant fluid is being added to the waste tank.

[0020] The shut off valve 10 may be used as part of a lavatory system 70on an airplane as shown in FIG. 2. The system 70 includes one or moretoilet bowls 74, a waste tank 80, a drain passage 82 for the waste tank80, and a pump 86. The exterior wall of an aircraft 94 and connectingfixture 92 are shown as well in FIG. 2. Waste is deposited in the toilet74 by aircraft passengers. Waste is flushed from the toilet 74 bydisinfectant fluid pumped into the toilet 74 by pump 86 and into thewaste tank 80.

[0021] At the end of a flight the waste tank 80 is sanitized. Thisprocess is typically performed by a ground crew using a lavatory cart100 as shown in FIG. 3. Referring back to FIG. 2, waste is drained fromthe waste tank by opening the drain passage 82 valve. Waste istransferred to a holding tank on the lavatory cart 100. The drainpassage 82 is then closed and the waste tank 80 filled with disinfectantfluid. Disinfectant fluid is added from a holding tank on the lavatorycart 100 to the waste tank 80 through the shut off valve 10. As thelevel of disinfectant fluid is rising within the waste tank 80, themagnetic actuator 60 is brought into proximity of the valve body 12 toclose off the flow of disinfectant fluid as shown in FIG. 4. Theautomatic shut off provided by the magnetic actuator allows the groundcrew to perform other tasks while the waste tank is being filled,without risking overfilling.

[0022] The lavatory system 70 may also include a tube 90 to house themagnetic actuator 60. The tube 90 is oriented alongside of the wastetank and liquid from the waste tank 80 can flow into the tube 90. In anembodiment of the invention, the tube 90 is next to the waste tank 80and is mounted in a vertically canted manner. The level of the fluidwithin the tube 90 is directly proportional to the level of fluid withinthe waste tank 80. When the actuator is a float, the float moves inresponse to level changes in the fluid within the tube 90. The tubeincludes one or more vents near its top to allow air to enter and beexpelled in order to avoid vacuum or over pressure conditions when fluidlevels in the waste tank change. As the fluid level in the tank 80reaches the top of the tank 80, the level of fluid in the tube causesthe actuator 60 to get close enough to the shut off valve 10 to move theflapper body 40. The flapper body 40 is then assisted into the sealposition by the fluid flowing through the valve 10 and flow into thetank 80 is stopped.

[0023] Additional advantages and modifications will readily appear tothose skilled in the art. For example, different locations of the tubemay be utilized. Different materials or composites may be used to formthe shut off valve. Also, the shut off valve may be used in a vacuumtransfer aircraft toilet system if disinfectant fluid is still usedduring service operations and there are ways where the disinfectantfluid can spill because of overfilling and cause problems. Therefore,the invention, in its broader aspects, is not limited to the specificdetails, the representative apparatus, and illustrative examples shownand described. Accordingly, departures may be made from such detailswithout departing from the spirit or scope of the applicant's generalinventive concept.

1. A shut off valve for regulating fluid flow comprising: an inletpassage in intermittent fluid communication with an outlet passage; amagnetic flapper body movable between a rest position and a sealposition between said inlet passage and said outlet passage; and amagnetic actuator that moves said flapper body from said rest positiontoward said seal position.
 2. The shut off valve of claim 1 wherein saidflapper body is positioned so that inlet fluid flow assists saidactuator in moving said flapper body into said seal position.
 3. Theshut off valve of claim 1 wherein said flapper body comprises a magneticmaterial.
 4. The shut off valve of claim 1 wherein said flapper body ismade from a non-magnetic material and includes one or more affixedmagnets.
 5. The shut off valve of claim 1 wherein said inlet passagefurther includes a check valve for preventing back flow.
 6. The shut offvalve of claim 1 further including a reset magnet whereby when saidmagnetic actuator is not within the proximity of said flapper body, saidflapper body is magnetically urged toward said rest position.
 7. Theshut off valve of claim 1 further including a bypass passage thatdiverts a small portion of said fluid flow to rinse said magneticactuator.
 8. The shut off valve of claim 1 wherein said outlet passagefurther includes a check valve for preventing back flow.
 9. A lavatorysystem for use on an airplane comprising: one or more toilets, eachtoilet including a drain passage for disposal of sanitary wastes; awaste tank attached to said drain passages from said toilets; a tube influid communication with said waste tank and oriented alongside saidwaste tank; a magnetic float within said tube whereby said float risesand falls in response to level changes within said waste tank; and ashut off valve for regulating flow of disinfectant fluid, said valveincluding: an inlet passage in intermittent fluid communication with anoutlet passage, said outlet passage directing fluid to said waste tank;and a magnetic flapper body movable between a rest position and a sealposition between said inlet passage and said outlet passage; wherebywhen a predetermined level is reached in said tank, said magnetic floatcomes within the proximity of said magnetic flapper body, said flapperbody is moved from said rest position and, with the assistance ofpressure from said disinfectant fluid flow into said seal position. 10.The lavatory system of section 9 further including a bypass passage thatdiverts a small portion of said fluid flow to rinse said magnetic float.11. The lavatory system of claim 9 wherein said flapper body comprises amagnetic material.
 12. The lavatory system of claim 9 wherein saidflapper body is made from a non-magnetic material and includes one ormore affixed magnets.
 13. The lavatory system of claim 9 wherein saidinlet passage further includes a check valve for preventing back flow.14. The lavatory system of claim 9 further including a reset magnetwhereby when said magnetic float is not within the proximity of saidflapper body, said flapper body is magnetically urged towards said restposition.
 15. The lavatory system of claim 9 wherein said outlet passagefurther includes a check valve for preventing back flow.
 16. Thelavatory system of claim 9 wherein said tube is oriented alongside saidwaste tank in a vertically canted manner.
 17. The lavatory system ofclaim 9 wherein said tube includes one or more vents at its top to allowthe passage of air.
 18. A method of refilling an aircraft's lavatorywaste tank comprising the steps of: draining said tank of sanitarywaste, said tank including an tube in fluid communication with saidwaste tank and oriented vertically alongside said waste tank and amagnetic float within said tube whereby said float rises and falls inresponse to fluid level changes within said waste tank; refilling saidtank with disinfectant fluid through a shut off valve, said shut offvalve including an inlet passage in intermittent fluid communicationwith an outlet passage, said shut off valve including a magnetic flapperbody movable between a rest position and a seal position between saidinlet passage and said outlet passage; and regulating disinfectant fluidflow with said shut off valve whereby when disinfectant fluid level inthe tank reaches a predetermined level the magnetic float acts to movethe magnetic flapper, with the assistance of the disinfectant fluid flowinto the seal position, thereby stopping the flow of disinfectant fluidinto the waste tank.
 19. The method of refilling of claim 18 furtherincluding a rinsing step wherein while refilling said tank withdisinfectant fluid, some of said fluid is diverted through a bypasspassage and rinses the magnetic float.